1. Field of the Invention
This invention relates to a method of transmitting encryption-resultant information and decrypting information. Also, this invention relates to an apparatus for transmitting encryption-resultant information and decrypting information. In addition, this invention relates to a method of recording encryption-resultant information and decrypting information on a recording medium. Furthermore, this invention relates to an apparatus for recording encryption-resultant information and decrypting information on a recording medium. In addition, this invention relates to a recording medium.
2. Description of the Related Art
It is known that original contents information is encrypted, and the encryption-resultant information and also decrypting information are recorded on an optical disc. Generally, the encryption-resultant information is assigned to a main recording area of the optical disc while the decrypting information is assigned to a lead-in area thereof. Disc players reproduce the encryption-resultant information and the decrypting information from the optical disc. Only disc players owned by legitimate users are able to decrypt the encryption-resultant information into the original contents information in response to the decrypting information.
It is conceivable that encryption-resultant information and decrypting information are recorded on separate areas of a magnetic tape. In this conceivable case, the following problems arise. Access to the decrypting information takes a long time during playback. There is some difficulty with playback from an intermediate point of the magnetic tape.
Also, it is conceivable that encryption-resultant information and decrypting information are recorded on a common area of a magnetic tape. In this conceivable case, a problem arises in the synchronization between the encryption-resultant information and the decrypting information during playback. In addition, the following problems arise. It is necessary to provide a surplus memory. Signal processing up to decoding takes a long time.